The overall objective of this research is to characterize those epidermal structural proteins which are primarily involved in normal pathologic keratinization. Differentiation products of epidermal cells, such as 60-80 angstrom units filaments and keratohyalian granules, will be isolated by established procedures. Their structural proteins, fibrous alpha- protein and sulfur-rich amorphous protein will be studied by biochemical and physicochemical methods in an effort to define the molecular architecture and chemical nature. Isolation and characterization of the polypeptide chains will be a major objective. The structural proteins present in normal horny cells will be dissociated into polypeptide chains and compared with polypeptide chains obtained from (1) fibrous alpha-protein and sulfur-rich amorphous protein and (2) structural proteins of pathologic horny cells. Pathologic horny scales will be collected from patients suffering from psoriasis and ichthyosis.